Ice making machines, or ice makers, typically comprise a refrigeration and water system that employs a source of refrigerant flowing serially through a compressor, a condenser, a thermal expansion device, an evaporator, and a freeze plate comprising a lattice-type cube mold thermally coupled with the evaporator. Additionally, typical ice makers employ gravity water flow and ice harvest systems that are well known and in extensive use. Ice makers having such a refrigeration and water system are often disposed on top of ice storage bins, where ice that has been harvested is stored until it is needed. Such ice makers may also be of the “self-contained” type wherein the ice maker and ice storage bin are a single unit. Such ice makers have received wide acceptance and are particularly desirable for commercial installations such as restaurants, bars, motels and various beverage retailers having a high and continuous demand for fresh ice.
The ice produced by such ice makers is either consumed as a food in beverages, comes in direct contact with food, and/or comes into direct contact with beverage containers that in turn come into direct contact a with a drinker's beverage, lips, and mouth. Therefore, ice is a food product, and an ice maker is a food preparing machine. As such, sanitizing and cleaning or descaling an ice maker on a regular basis is a recommended practice.
In particular, sanitizing eliminates harmful bacteria, viruses and protozoa that thrive in a cold ice-making environment. These microscopic organisms can be either airborne or waterborne. Municipal water systems are relatively free of harmful waterborne organisms due to chlorine treatment. Water filtration can also provide protection against waterborne bacterial contamination. However, airborne organisms can still migrate to the ice maker. Bacteria, viruses, and protozoa can also adhere to moist areas on the inside of the ice maker and thrive in the cool, damp conditions. This may result in mold, algae, and slime buildup. Slime is usually a jellylike substance that is made up of algae, mold, and yeast spores that can become either airborne or waterborne. Some of these bacteria and viruses can make people ill. Accordingly, sanitizing an ice maker is an important task that should not be neglected. Various types of food-grade sanitizing agents are typically used to kill bacteria and other biologics that may be attracted to ice makers.
A different process from sanitizing an ice maker is descaling, often referred to as cleaning. Descaling an ice maker removes minerals and metals that build up in the water system and freeze plate of the ice maker and most particularly the sump used to catch and hold cooling water that falls from the freeze plate. Minerals and metals generally comprise sodium, potassium, calcium, magnesium, iron, copper, manganese, phosphorus, and zinc in amounts that vary with locale and type of water source.
As the ice maker begins to form ice on the freeze plate, minerals and metals tend to build up concentration in the sump and begin to “wash out”, or fall out of solution, to form a solid build-up in the lowest portion of the water system, the sump. This is because pure water tends to freeze first. This causes the mineral and metal concentration in the unfrozen water to increase as purer liquid water is removed in the form of ice. This phenomenon is also evident when standing water freezes into an ice cube. The clearest water will tend to be at the outer edges of the cube, which freeze first, and a cloud of minerals eventually becomes trapped at the center of the cube.
Irrespective of the type of ice made by an ice maker or the method used to make the ice, a cleaner ice maker and purer water will form harder, more sanitary, and clearer ice. Many ice makers include built-in flushing and purging cycles that direct any water from the sump to a drain when a predetermined amount of water has been turned to ice. This flushing of high mineral concentration water helps to reduce mineral formation in the sump, but eventually minerals will still form in the sump and elsewhere in the water system. After a period of time, the minerals must still be removed to keep the ice clear and conditions sanitary.
When removing mineral buildup, or scale, from an ice maker, food grade acids are used to help dissolve the mineral buildup. Heavier scale deposits may require soaking in the acid solution. Manual scrubbing, scraping or wiping is also effective and sometimes necessary to remove minerals and metals from the sump and other parts of the maker.
While critical to the safe and healthy operation of ice makers, descaling and/or sanitizing of ice makers is often neglected because such maintenance is time consuming. Descaling and sanitizing requires the ice maker to be taken offline for a period of time and is therefore inconvenient. These processes also require that service personnel be present for most of the process. Since there are two separate processes, service personnel cannot start one and leave. They must remain at or near the ice maker until the descale process is complete so that they can initiate the sanitize process.